Therapeutics for weakened-eyesight are numerous. The primary method is to strengthen ciliary muscles of the eyeball. This helps control functions of the crystalline lens such as in eyeball gymnastics. Another method is to use a concave lens and/or a convex lens.
Causes of amblyopia are various, but one cannot depend on the known methods of treatment for improving weak eyesight. In particular, symptoms of amblyopia by cataract were thought to be incurable. As for treatment of these symptoms, the obsolete way of therapeutics is not acceptable.
Emmetropia is when the eye is in focus, and ametropia is when the total refractive index of an eye is out of harmony with the axis of the eyeball. There are three kinds of ametropia, i.e. myopia, hypermetropia and astigmatism.
Causes of mytropia are various. Generally, some people read a book for a long time and their distance vision is effected. Thus, that person is liable to develop mytropia. Mytropia is an immovable state where the crystalline lens is in a state of tension with a ciliary muscle. Mytropia is classed in various ways, i.e. malignant myopia and pseudomyopia, etc.
On the other hand, hypermetropia is a symptom were the image of a body is located at the back of the retina. Repeatedly, metropia, as well as hypermetropia, is basically caused by the abnormal symptom of the crystalline lens. Also, it is known that cataracts cause amblyopia.